1. Field of the Invention
The present invention relates generally to a control device for regulating alternate current (AC) power output, and in particular to a power regulation device that is digitally controlled.
2. Description of the Prior Art
AC power regulation is conventionally realized by using a triac. A triggering circuit controls the conducting angle of the triac for controlling the power transmitted to a load. Since this is analog control, rather than digital control, only simple control can be achieved, such as the application to dimmer.
In the transmission of AC power, electrical current flows through a long electrical wire to reach nodes of end users. Since there are a great number of end user nodes located along the power transmission line, the voltage that actually sensed at the end user nodes are different from node to node. The node that is located upstream may obtain a higher voltage, while that downstream has a lower voltage. In addition, the time when a peak amount of power is required, the voltage that the end user node may have is lower than that obtained in the time when a non-peak amount of power is required.
Due to such a variation that is encountered by all the electrical power suppliers around the world, power-related regulations provide an allowance for variation of the voltage supplied to the end user nodes, such as xc2x110%xcx9cxc2x120%. Based on such a regulation of acceptable variation of power supply, electrical manufacturers make electrical appliances that have a rating power corresponding to the regulation-accepted power variation.
It is thus aimed to provide a power regulation device that reduces the variation in order to ensure proper operation of the electrical appliances.
Thus, an object of the present invention is to provide a digital control device for regulating AC power that is supplied to a load.
Another object of the present invention is to provide a digitally controlled power regulation device connected between a power source and a load wherein the power regulation device detects an output voltage of the power source and provides a voltage having a lower level to a load when the detected output voltage of the power source is beyond a preset reference.
A further object of the present invention is to provide digital control device for saving power consumption by comparing input voltage with a preset reference and automatically regulating an output voltage based on the result of comparison.
To achieve the above objects, in accordance with the present invention, there is provided a power regulation device connected between a power source and a load for receiving receive a first voltage from the power source and providing a second voltage to the load. The power regulation device comprises a first voltage detection circuit for detecting the first voltage and a second voltage detection circuit for detecting the second voltage. A controller receives signals representing the first and second voltages and compares the signals with preset references to issue control signals. A switch circuit is connected between the power source and the load and is coupled to and controlled by the controller. The switch circuit is controlled by the control signals of the controller to change from a first state to a second state for selectively passing the first voltage and inducing different levels of the second voltage which are associated with different powers supplied to the load.